Bicycle riding is excellent exercise. Vigorous biking is wonderful for general body health in that it produces increased heart pumping to supply increased blood to the large leg muscles. There is not the constant leg impact associated with jogging.
In the basic bicycle design, a chain sprocket on the rear wheel of the bicycle is driven by a bicycle chain through a chain sprocket powered by a pedal shaft driven by the legs and feet of the bicyclist operating on a pair of bicycle pedals attached to the pedal shaft.
For the typical bicycle to move in the forward direction, the bicyclist applies force to the pedals causing them to rotate in the same rotational direction as the wheels of the bicycle for forward motion. (This rotational direction is hereinafter referred to as the "forward direction". The reverse direction is hereinafter referred to as the "reverse direction". In some cases we will refer to rotational direction of various parts of the bicycle as either clockwise or counter-clockwise. In such cases it will be assumed that we are viewing the bicycle from its right side, and in all of the figures we will be viewing the bicycle and the bicycle parts from the right side.) Typical bicycles in use today do not operate in reverse. For these bicycles the pedals can be rotated in the counter-clockwise direction when the bicycle is moving forward, but such motion provides no force to the wheels of the bicycle. Thus, with prior art bicycles, force can be applied to the wheels of the bicycle only by rotating the pedals in the forward direction. Normally force is applied to the rear wheel only on the downward stroke of the pedals; however it is fairly common practice for bicyclists to clamp their shoes to the pedals. Then force can also be applied to the rear wheel on the upward stroke of the pedals.
With prior art bicycles there is no way to apply forward force to the wheels of the bicycle with a reverse motion of the pedals. Such an improvement would increase the value of the bicycle as an exercise device and also provides an alternate method of propulsion emphasizing use of different leg and related muscles which would increase endurance for long bike trips.
What is needed is a bicycle mechanism which will permit the bicyclists to apply forward driving force to the wheels of the bicycle with both forward and reverse motion of the pedals to obtain these performance enhancements.